用MWECR CVD系统制备具有非晶微晶两相结构的硅薄膜研究.docx

用MWECRCVD系统制备具有非晶微晶两相结构的硅薄膜研究
Abstract
Inthispaper,westudiedthepreparationofsiliconthinfilmswithamorphous/microcrystallinedual-phasestructureusingtheMWECRCVDsystem.Thedepositionparameterswereoptimized,andthepropertiesoftheobtainedfilmswerecharacterizedbyvarioustechniquessuchasXRD,SEM,Ramanspectroscopy,andAFM.Theresultsshowedthatthedual-phasesiliconfilmshadimprovedelectricalandopticalpropertiescomparedtopureamorphoussiliconormicrocrystallinesiliconfilms.Theeffectsofdepositionparametersonthepropertiesofthedual-phasefilmswerediscussed,andthepotentialapplicationsofthesefilmsinelectronicandphotovoltaicdeviceswerealsodiscussed.
Introduction
Amorphoussilicon(a-Si)andmicrocrystallinesilicon(μc-Si)havebeenwidelystudiedandusedinvariouselectronicandphotovoltaicdevicesduetotheiruniquepropertiessuchaswidebandgap,highopticalabsorptioncoefficient,andlow-temperaturedeposition.However,purea-Siandμc-Sifilmstypicallyexhibitsomedrawbackssuchaspoorelectronictransportproperties,lowcarriermobility,andinferiorstabilityunderillumination.Thecombinationofa-Siandμc-Sistructuresinonematerialcouldtakeadvantageoftherespectivepropertiesofeachphaseandmitigatetheirdrawbacks.
TheMWECRCVDsystemisanefficientandconvenienttechniquefordepositingsiliconfilmswithdesiredproperties.Inthissystem,microwavesareusedtodissociatethereactivegas(usuallysilane)intoatomicormolecularspecies,whichthenreactanddepositonthesubstrate.Byadjustingthedepositionconditions,suchasgasflowrate,pressure,temperature,andmicrowavepower,thestructureandpropertiesofthedepositedfilmscanbetailored.
Inthisstudy,a-Si/μc-Sidual-phasesiliconfilmsweresynthesizedusingtheMWECRCVDsystem.Theeffectsofdepositionparametersonthestructureandpropertiesofthefilmswereinvestigated.
Experimental
TheMWECRCVDsystemusedinthisstudyconsistedofaquartztubereactor,amicrowavegenerator,agasdeliverysystem,andasubstrateholder.High-puritysilane(SiH4)gaswasusedastheprecursor,andhydrogengas(H2)wasusedasthecarriergas.Thedepositiontemperaturewassetat250°C,andthepressurewasmain